Metal organic frameworks, their synthesis and use

ABSTRACT

A novel metal organic framework, EMM-33, is described having the structure of UiO-67 and comprising bisphosphonate linking ligands. EMM-33 has acid activity and is useful as a catalyst in olefin isomerization. Also disclosed is a process of making metal organic frameworks, such as EMM-33, by heterogeneous ligand exchange, in which linking ligands having a first bonding functionality in a host metal organic framework are exchanged with linking ligands having a second different bonding functionality in the framework.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/501,154 filed May 4, 2017, which is herein incorporated byreference in its entirety.

FIELD

The present disclosure relates to metal organic frameworks (MOFs), to aparticular novel MOF, designated herein as EMM-33, and to the synthesisof MOFs and their use, particularly in catalytic applications.

BACKGROUND

Metal-organic frameworks (MOFs) are a relatively new class of porousmaterials that are comprised of metal ion/oxide secondary building units(SBUs) interconnected by organic linking ligands. MOFs are characterizedby low densities, high internal surface areas, and uniformly sized poresand channels. For example, U.S. Pat. No. 8,653,292 describes Zr MOFshaving a surface area of at least 1020 m²/g or, if functionalized,having a surface area of at least 500 m²/g. As a result of theseadvantageous properties, MOFs have been investigated extensively forapplications in gas separation and storage, sensing, catalysis, drugdelivery, and waste remediation. The wide array of potentialapplications for MOFs stem from the nearly infinite combination oforganic ligands and secondary building units available. Regardless ofthis diversity, many materials have been left undiscovered due tolimitations in the synthetic protocols typically employed for MOFsynthesis. The relatively high temperatures and long crystallizationtimes employed to synthesize metal-organic frameworks preclude theincorporation of sensitive moieties. Furthermore, the multipleconformations possible between the ligand and metal SBUs make predictingand directing structure challenging.

Recently a novel method of accessing new MOF materials from a startinghost framework has been realized through the use of post-syntheticlinker and ion exchange. This method, referred to in the literature asSolvent Assisted Ligand Exchange (SALE) or Post-Synthetic Exchange(PSE), is discussed by, for example, Karagiaridi, O.; Bury, W.;Mondloch, J. E.; Hupp, J. T.; Farha, O. K. in “Solvent-Assisted LinkerExchange: An Alternative to the De Novo Synthesis of UnattainableMetal-Organic Frameworks”, Angew. Chem. Int. Ed. 2014, 53, 4530-4540).This technique has allowed for the development of novel materials whichhave thus far eluded researchers.

One example of the SALE process is disclosed in U.S. Pat. No. 8,920,541using a species of MOF known as a zeolitic imidazolate framework or ZIF,as the host framework. In particular, the '541 patent discloses a methodfor exchanging the imidazolate linker in a zeolitic imidazolateframework composition, said method comprising the steps of: (a)providing a first zeolitic imidazolate framework composition having atetrahedral framework comprising a general structure, M¹-IM^(a)-M²,wherein M¹ and M² comprise the same or different metal cations, andwherein IM^(a) is an imidazolate or a substituted imidazolate linkingmoiety; (b) providing a liquid composition comprising IM^(b), whereinIM^(b) is an imidazolate or a substituted imidazolate which is differentfrom IM^(a); and (c) contacting the first zeolitic imidazolate frameworkcomposition with the liquid composition under conditions sufficient toexchange at least a portion of IM^(a) with at least a portion of IM^(b)and to produce a second zeolitic imidazolate framework composition,M¹-IM^(c)-M², wherein IM^(c) comprises IM^(b), and wherein the frameworktype of the second zeolitic imidazolate framework composition isdifferent from the framework type obtained when a zeolitic imidazolateframework composition is prepared by crystallizing a liquid reactionmixture comprising a solution of M¹, M² and IM^(b). One notable resultof this work was the complete exchange of 2-methylimidazole (mim) inZIF-8 for 5-azabenzimidazole (5-abim) to isolate a novel ZIF framework,EMM-19, composed of 5-abim linkers connected to zinc tetrahedra in asodalite (SOD) topology. This particular structure had been hypothesizedto be unobtainable due to the propensity of azabenzimidazole linkers toform ZIFs with LTA-type topologies. This discovery allowed for thedevelopment of materials with highly desirable CO₂ adsorptioncharacteristics not observed in the nearly identical ZIF-7.

Another type of relevant post-synthetic transformation is SolventAssisted Ligand Incorporation (SALI), in which functional moieties aregrafted onto the ligands and/or secondary building units of MOFs. Forexample, Hupp and coworkers demonstrated that the treatment of theZr-based framework, NU-1000, results in the dehydration and grafting ofpendant carboxylate and phosphonate moieties onto the secondary buildingunit (See MOF Functionalization via Solvent-Assisted LigandIncorporation: Phophonates vs Carboxylates. Inorg. Chem. 2015, 54,2185-2192 and Perfluoroalkane Functionalization of NU-1000 viaSolvent-Assisted Ligand Incorporation: Synthesis and CO₂ AdsorptionStudies. J. Am. Chem. Soc. 2013, 135, 16801-16804. Interestingly, thistransformation occurs without loss of crystallinity of the parentmaterial and serves to tune the adsorption properties of the resultingmaterial.

Despite these advances, there remains a need for new methods ofpost-synthesis modification of MOF structures and particularly for thosemethods which allow the production of ligand/SBU combinations that aredifficult or impossible to access by conventional MOF synthesis routes.

SUMMARY

According to the present disclosure, it has now been found that linkerexchange can be used with a MOF comprising a first organic linkingligand having a first bonding functionality to partially or completelyreplace the first ligand with a second organic linking ligand having asecond bonding functionality different from the first bindingfunctionality. In particular, it has been found that an organic linkingligand with monoprotic acid bonding functionality, such as a carboxylateligand, can be partially or completely replaced with an organic linkingligand having polyprotic acid bonding functionality, such as aphosphonate ligand, to allow incorporation of acidic behavior in a MOF.Based on this technique a new MOF, designated as EMM-33, has beenproduced by exchange of the biphenyldicarboxylate linker in UiO-67 witha biphenylbisphosphonate linker. EMM-33 is an active catalyst for avariety of organic conversion reactions, including olefin isomerization.The terms “linker” and “ligand” can be used interchangeably herein.

In one aspect, the present disclosure resides in a metal organicframework having the structure of UiO-67 and comprising bisphosphonatelinking ligands.

In a further aspect, the present disclosure resides in a metal organicframework comprising Zr₆O₄(OH)₄ octahedra interconnected bybisphosphonate linking ligands.

In some embodiments, the metal organic framework comprisesbiphenylbisphosphonate ligands wherein each phenyl group may optionallybe functionalized with one or more electron withdrawing groups.

In yet a further aspect, the present disclosure resides in a process forexchanging an organic linking ligand in a metal organic framework, theprocess comprising:

(a) providing a first metal organic framework comprising athree-dimensional microporous crystal framework structure comprisingmetal-containing secondary building units connected by first organiclinking ligands having a first bonding functionality with the secondarybuilding units,

(b) providing a liquid medium containing an organic compound capable ofreacting with the secondary building units to produce second organiclinking ligands having a second bonding functionality with the secondarybuilding units different from the first binding functionality; and

(c) contacting the first metal organic framework with the liquid mediumunder conditions effective for the organic compound to react with thesecondary building units in the first metal organic framework andexchange at least some of the first organic linking ligands with secondorganic linking ligands and produce a second metal organic framework.

In some embodiments, the first organic linking ligand is bonded to eachsecondary building unit through a monoprotic acid group and the secondorganic linking ligand is bonded to each secondary building unit througha polyprotic acid group.

In another aspect, the present disclosure resides in an organic compoundconversion process, such as an olefin isomerization process, comprisingcontacting an organic compound-containing feed with a catalystcomprising the metal organic framework described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the powder X-ray diffraction patterns of a UiO-67 startingmaterial and its phosphonate-exchanged products after reaction with0.22, 0.45, 0.92 and 1.8 mol. equivalents of 4,4′-biphenylbisphosphonicacid according to the process of Example 1.

FIG. 2 shows the N₂ gas adsorption curves of a UiO-67 starting materialand its phosphonate-exchanged products after reaction with 0.22, 0.45,0.92 and 1.8 mol. equivalents of 4,4′-biphenylbisphosphonic acidaccording to the process of Example 1.

FIG. 3 shows the IR spectra of 4,4′-biphenyldicarboxylic acid,4,4′-biphenylbisphosphonic acid, UiO-67 and its phosphonate-exchangedproducts after reaction with 0.22, 0.45, 0.92 and 1.8 mol. equivalentsof 4,4′-biphenylbisphosphonic acid according to the process of Example1.

FIG. 4 shows the ³¹P MAS NMR spectra of biphenylbisphosphonic acid andphosphonate-exchanged UiO-67 after reaction with 0.22 mol. equivalentsof 4,4′-biphenylbisphosphonic acid according to the process of Example1.

FIG. 5 shows the powder X-ray diffraction patterns of EMM-35 undervarious levels of exchange.

FIG. 6 shows the 19F MAS NMR of EMM-35 (red and black) as well as thepure perfluoro-4,4′-biphenylbisphosphonic acid(blue).

FIG. 7 shows the ATR-IR spectra of EMM-35 as well as UiO-67 and thephosphonate starting material.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Disclosed herein is a novel metal organic framework, designated EMM-33,which has the structure of UiO-67 and comprises bisphosphonate linkingligands, optionally together with dicarboxylate linking ligands, and itsuse as a catalyst. Also disclosed is a process for producing metalorganic frameworks, such as EMM-33, by heterogeneous ligand exchange. Inthis process, first organic linking ligands interconnecting secondarybuilding units (SBUs) in a host metal organic framework through a firstbonding functionality are partially or completely replaced by secondorganic linking ligands which bond to the SBUs through a second,different functionality.

UiO-67 is a metal organic framework composed of Zr₆O₄(OH)₄ octahedratwelve-fold bonded to adjacent octahedra by 4,4′-biphenyldicarboxylateligands. UiO-67 is reported to have an X-ray diffraction pattern whichincludes the characteristic lines listed in Table 1 below:

TABLE 1 Interplanar d-Spacing (Å) Two-theta Relative Intensity (100 ×I/Io) 15.5197 5.690 100 13.4405 6.571 25.8 9.298 9.298 1.9 8.1049 10.9073.7 7.7599 11.394 11.3 6.7202 13.164 4.1 6.0108 14.726 0.9 5.4870 16.1400.2 5.1732 17.126 1.9 4.7519 18.658 0.3 4.5437 19.521 2.1 4.4802 19.8012.3 4.2502 20.883 0.2 4.0993 21.662 0.3

EMM-33 is a metal organic framework having the same SBUs as UiO-67,namely Zr₆O₄(OH)₄ octahedra, in which some or all of the4,4′-biphenyldicarboxylate ligands joining adjacent octahedra have beenexchanged by 4,4′-biphenylbisphosphonate linking ligands. EMM-33 isisostructural with UiO-67 and so generally has a similar characteristicX-ray diffraction pattern as UiO-67. However, as shown in FIG. 1, athigh levels of ligand exchange some crystallinity may be lost resultingin certain lines in the normal X-ray pattern of UiO-67 being diminishedin intensity. In some embodiments, therefore, it may be desirable tocontrol the ligand exchange so that no more than 30%, such as no morethan 25%, for example no more than 20% of the 4,4′-biphenyldicarboxylateligands in the UiO-67 parent material are replaced by4,4′-biphenylbisphosphonate ligands. Typically, at least 15% of the4,4′-biphenyldicarboxylate ligands in the UiO-67 parent material arereplaced by 4,4′-biphenylbisphosphonate ligands.

One important difference between EMM-33 and UiO-67 concerns the natureof the bonding functionality of the different ligands. Thus, in UiO-67the bonding to each Zr₆O₄(OH)₄ octahedron is via a monoprotic carboxylicacid group so that in the final MOF there is little or no remaining acidfunctionality. In contrast, in EMM-33 the bonding to each Zr₆O₄(OH)₄octahedron is via a diprotic phosphonic acid group so that the final MOFhas acid functionality and, as will be discussed in more detail below,exhibits catalytic activity for organic conversion reactions, such asolefin isomerization. By suitable functionalization on one or more ofthe phenyl groups of 4,4′-biphenylbisphosphonate ligands, such as withelectron withdrawing groups, this acidity can be increased, potentiallywith an increased catalytic activity of the final MOF. Suitable electronwithdrawing groups include fluoro, chloro, bromo, iodo and nitro groups.

The process used to produce EMM-33 potentially has wide application inMOF synthesis and involves solvent assisted ligand exchange of a hostMOF including first organic ligands having a first SBU bondingfunctionality by reaction in a liquid medium with an organic compoundcapable of reacting with the SBUs of the host MOF to produce secondorganic linking ligands having a second bonding functionality with theSBUs different from the first bonding functionality. Of course in thecase of EMM-33 synthesis, the host MOF is UiO-67 having Zr₆O₄(OH)₄octahedra interconnected by linking ligands having two monoproticcarboxylic acid groups and the replacing ligands have two diproticphosphonic acid groups. However, the process is equally applicable toMOFs having different SBUs, including other metal ion/oxide-containinggroups, especially groups comprising at least one tetravalent transitionmetal, such as hafnium, titanium and/or zirconium. Similarly, theprocess is applicable to host MOFs containing other organic linkingligands than 4,4′-biphenyldicarboxylate ligands, including otheraromatic or non-aromatic dicarboxylate ligands, as well as ligands whosebonding functionality is not limited to monoprotic acid functionality,including, for example, zeolitic imidazolate frameworks or ZIFs andpyridine-containing frameworks. Further, the process can be used withother exchange ligands than biphosphonate ligands, whether or not havinga polyprotic acid bonding functionality, such as sulfonates andboronates.

In the linker exchange process described herein, a first or host metalorganic framework (MOF) is provided in which the host MOF comprises athree-dimensional microporous crystal framework structure comprisingmetal-containing secondary building units connected by first organiclinking ligands having a first bonding functionality with the secondarybuilding units. In some embodiments, it may be desirable to removeunreacted species or impurities from the as-synthesized form of host MOFprior to linker exchange. These unreacted species or impurities may beremoved by appropriate techniques, e.g., involving washing and drying.For example, the as-synthesized form of the host MOF may be washed witha suitable solvent, such as DMF, followed by solvent exchange withethanol, acetonitrile, or the like, decanting solvent and drying, forexample, under vacuum at about 250° C. Alternatively, a first MOFcomposition sufficiently (substantially) free of unreacted species orimpurities may be purchased from commercial vendor.

In another step of the process, a liquid medium is provided containingan organic linker compound capable of reacting with the secondarybuilding units in the host MOF to produce second organic linking ligandshaving a second bonding functionality with the secondary building unitsdifferent from the first bonding functionality. For example, the firstbonding functionality may be via a monoprotic acid functionality whereasthe second bonding functionality may be via a polyprotic, such as adiprotic, acid functionality The organic linker compound may be presentin the liquid medium, for example, in the form of the protonated form ofthe linker composition and/or in the form of a salt of the composition.

The liquid medium may comprise a solution of the organic linker compoundin a solvent. The solvent may be a polar organic solvent, such asN,N-dimethylformamide (DMF), N,N-diethylformamide (DEF),N,N-dimethylacetamide (DMAc), 1,3-dimethylpropyleneurea (DMPU), asulfoxide (e.g., dimethylsulfoxide or DMSO), a phosphoramide (e.g.,hexamethylphosphoramide), an alcohol (e.g. butanol), acetonitrile(MeCN), triethylamine (TEA), or a combination thereof. Alternatively,though not strictly organic, aqueous solvents such as aqueous ammoniaand ethanol mixtures, can be used as solvents for the linkercompound(s).

Though polar organic compounds such as N,N-dimethylformamide (DMF) aresuggested as solvents herein, it should be understood that a solvent (orsolvent system) useful in the methods according to the invention and/oruseful in making products according to the invention should at least beable to solvate and/or solubilize the reactants to the extent necessaryto allow reaction to occur at a reasonable rate (or over a reasonablereaction time). They can also typically be present in a substantiallyliquid phase at operating/reaction conditions (and optionally butpreferably also at STP).

In certain embodiments, solvents (and/or solvent systems) particularlyuseful in the invention can additionally or alternately exhibit arelatively high vapor pressure and/or a relatively low boiling point.For instance, in some such embodiments, a relatively high vapor pressurecan represent at least 2.5 kPa at about 20° C., for example at leastabout 3.0 kPa at about 20° C., at least about 3.5 kPa at about 20° C.,at least about 4.0 kPa at about 20° C., at least about 4.5 kPa at about20° C., at least about 5.0 kPa at about 20° C., at least about 5.5 kPaat about 20° C., at least about 6.0 kPa at about 20° C., at least about6.5 kPa at about 20° C., at least about 7.0 kPa at about 20° C., atleast about 7.5 kPa at about 20° C., at least about 8.0 kPa at about 20°C., at least about 8.5 kPa at about 20° C., at least about 9.0 kPa atabout 20° C., or at least about 9.5 kPa at about 20° C. Optionally, ifan upper boundary on vapor pressure is needed and/or desired, therelatively high vapor pressure can be about 30 kPa or less at about 20°C., e.g., about 25 kPa or less at about 20° C., about 20 kPa or less atabout 20° C., about 15 kPa or less at about 20° C., or about 10 kPa orless at about 20° C. Additionally or alternately, in some suchembodiments, a relatively low boiling point can represent 99° C. orless, e.g., about 98° C. or less, about 96° C. or less, about 95° C. orless, about 93° C. or less, about 91° C. or less, about 90° C. or less,about 88° C. or less, about 86° C. or less, about 85° C. or less, about83° C. or less, about 81° C. or less, or about 80° C. or less.Optionally, if a lower boundary on boiling point is needed and/ordesired (preferably, the solvent can have a boiling point above ambienttemperature, so as to be in a liquid phase), the relatively low boilingpoint can be at least about 25° C., e.g., at least about 30 ° C., atleast about 35° C., at least about 40° C., at least about 45° C., atleast about 50° C., at least about 55° C., at least about 60° C., atleast about 65° C., at least about 70° C., at least about 75° C., or atleast about 80° C. One such non-limiting example of a solvent systemhaving both a relatively low boiling point and a relatively high vaporpressure includes a mixture of acetonitrile and triethylamine.

In another step of the present process, the host MOF is contacted withthe liquid medium comprising organic linker compound. This contact maytake place by combining (1) the host MOF, (2) the solvent, and (3) asource of organic linker compound in any order. For example, host MOFand organic linker compound may first be combined, and the solvent maybe added to this combination, accomplishing the simultaneous formationof a liquid medium comprising the organic linker compound and contact ofthis composition with the host MOF. In a convenient embodiment, thesource of organic linker compound can first be dissolved in the solvent,and either the resulting solution can be added to the host MOF or thehost MOF can be added to the solution.

The amount of organic linking ligand used in the contacting step may beselected so that the molar ratio of the organic linking compound tofirst organic linking ligand in the host MOF is from 0.01 to 10, e.g.,from 0.02 to 5, from 0.03 to 1, from 0.04 to 1, from 0.05 to 0.9, from0.1 to 0.8, from 0.1 to 0.7, from 0.1 to 0.6, from 0.1 to 0.5, from 0.1to 0.4.. In particular, where less than complete exchange of the firstorganic linking ligand is desired, the molar ratio of the organiclinking compound to first organic linking ligand in the host MOF isadvantageously below 1.

The combined mixture of the host MOF with the liquid medium comprisingthe organic linking compound can be maintained under conditionssufficient to achieve at least partial exchange of the first linkingligand with the second linking ligand and produce the second MOF. Thecontact may take place for a sufficient time to achieve at least partialexchange, e.g., from at least 1 hour to as much as 10 days, from 1 hourto 7 days, from 1 hour to 5 days, from 1 hour to 3 days, from 2 hours to10 days, from 2 hours to 7 days, from 2 hours to 5 days, from 2 hours to3 days, from 4 hours to 10 days, from 4 hours to 7 days, from 4 hours to5 days, from 4 hours to 3 days, from 8 hours to 10 days, from 8 hours to7 days, from 8 hours to 5 days, from 8 hours to 3 days, from 12 hours to10 days, from 12 hours to 7 days, from 12 hours to 5 days, from 12 hoursto 3 days, from 18 hours to 10 days, from 18 hours to 7 days, from 18hours to 5 days, from 18 hours to 3 days, from 24 hours to 10 days, from24 hours to 7 days, from 24 hours to 5 days, or from 24 hours to 3 days.The temperature of the combined mixture of the host MOF with the liquidmedium comprising the organic linking compound may range, for example,from a temperature of about -78° C. (dry-ice bath temperature) to theboiling temperature of the solvent (the normal boiling point ofN,N-dimethylformamide is about 153° C. and of dimethylsulfoxide is about189° C.), from about 0° C. (ice water bath temperature) to at least 10°C. below the boiling temperature of the solvent, or from about 15° C. toat least 15° C. below the boiling temperature of the solvent (oralternately to about 100° C.). When contact takes place in a pressurizedvessel, the temperature may exceed the boiling temperature of thesolvent. For example, the contact may take place at room temperature orgreater, such as from about 18° C. to about 200° C. or from about 75° C.to about 150° C.

After the contacting is complete, the second MOF may be recovered andtreated, if necessary or desired (e.g., to remove molecules from thepore space of the second MOF). This treatment may involve techniques foractivating the as-synthesized form of a MOF prepared by solvothermalmethods, for example, as described in U.S. Pat. Nos. 8,314,245 and8,071,063. For example, the recovered MOF may be washed and then solventexchanged with acetonitrile and dried. Finally the driedacetonitrile-exchanged product may be placed under vacuum, e.g., lessthan about 10 mTorr at about 180° C. for about 18 hours, to yield theactivated form of the MOF.

Depending on the nature of the second organic linking ligands and, ifstill partially present, the first organic linking ligands, theresultant activated second MOF may have a variety of uses, such as anadsorbent for gases such as hydrogen, nitrogen, oxygen, inert gases,carbon monoxide, carbon dioxide, sulfur dioxide, sulfur trioxide,hydrogen sulfide, ammonia, methane, natural gas, hydrocarbons andamines. In addition, where, as with EMM-33, the second MOF has acidfunctionality, other potential uses are in organic compound conversionreactions. Thus, in the case of EMM-33, one such catalytic use is incatalytic olefin isomerization, namely in shifting the position of thedouble bond in a C₃₊ olefin, for example converting 2-methyl-2-penteneto 2-methyl-1-pentene. Such a process can, for example, be conducted bycontacting a source of the olefin to be isomerized with EMM-33 at atemperature from about 200° C. to about 400° C., such as from about 250°C. to about 350° C.

The invention can additionally or alternatively include one or more ofthe following embodiments.

Embodiment 1. A metal organic framework having the structure of UiO-67and comprising bisphosphonate linking ligands.

Embodiment 2. The metal organic framework of embodiment 1 and comprisingbiphenylbisphosphonate linking ligands, preferably4,4′-biphenylbisphosphonate linking ligands.

Embodiment 3. The metal organic framework of embodiment 1 or embodiment2 and further comprising biphenyldicarboxylate linking ligands.

Embodiment 4. A metal organic framework comprising Zr₆O₄(OH)₄ octahedrainterconnected by bisphosphonate linking ligands.

Embodiment 5. The metal organic framework of embodiment 4 and comprisingZr₆O₄(OH)₄ octahedra interconnected by biphenylbisphosphonate linkingligands, preferably 4,4′-biphenylbisphosphonate linking ligands.

Embodiment 6. The metal organic framework of embodiment 2 or embodiment5, wherein at least one of the phenyl groups of thebiphenylbisphosphonate linking ligands is substituted with one or moreelectron withdrawing groups.

Embodiment 7. The metal organic framework of embodiment 1 and furthercomprising dicarboxylate linking ligands.

Embodiment 8. A metal organic framework comprising octahedral nodes atleast 6 zirconium atoms and at least 6 oxygen atoms interconnected bybiphenyldicarboxylate ligands and at least one bisphosphonate linkingligand.

Embodiment 9. The metal organic framework of embodiment 8, wherein thebisphosphonate linking ligand is a biphenylbisphosphonate linkingligand, preferably a 4,4′-biphenylbisphosphonate linking ligand.

Embodiment 10. The metal organic framework of embodiment 8 or embodiment9, wherein at least one of the phenyl groups of thebiphenylbisphosphonate linking ligand is substituted with one or moreelectron withdrawing groups.

Embodiment 11. The metal organic framework of any one of embodiments 1to 10, wherein the metal organic framework comprises at least onetetravalent transition metal.

Embodiment 12. The metal organic framework of embodiment 11, wherein theat least one tetravalent transition metal is selected from the groupconsisting of hafnium, titanium and zirconium.

Embodiment 13. A process for exchanging an organic linking ligand in ametal organic framework, the process comprising:

(a) providing a first metal organic framework comprising athree-dimensional microporous crystal framework structure comprisingmetal-containing secondary building units to connected by first organiclinking ligands having a first bonding functionality with the secondarybuilding units,

(b) providing a liquid medium containing an organic compound capable ofreacting with the secondary building units to produce second organiclinking ligands having a second bonding functionality with the secondarybuilding units different from the first bonding functionality; and

(c) contacting the first metal organic framework with the liquid mediumunder conditions effective for the organic compound to react with thesecondary building units in the first metal organic framework andexchange at least some of the first organic linking ligands with secondorganic linking ligands and produce a second metal organic framework.

Embodiment 14. The process of embodiment 13, wherein the first organiclinking ligand is bonded to each secondary building unit through amonoprotic acid group.

Embodiment 15. The process of embodiment 13 or embodiment 14, whereinthe first organic linking ligand comprises a carboxylic acid, preferablyan aromatic dicarboxylic acid, more preferably a biphenyldicarboxylicacid.

Embodiment 16. The process of any one of embodiments 13 to 15, whereinthe second organic linking ligand is bonded to each secondary buildingunit through a polyprotic acid group, preferably a diprotic acid group.

Embodiment 17. The process of any one of embodiments 13 to 16, whereinthe second organic linking ligand comprises a phosphonic acid,preferably an aromatic bisphosphonic acid, more preferably abiphenylbisphosphonic acid.

Embodiment 18. The process of any one of embodiments 13 to 17, whereinthe secondary building units comprise at least one tetravalenttransition metal, preferably at least one metal selected from the groupconsisting of hafnium, titanium and zirconium.

Embodiment 19. The process of any one of embodiments 13 to 18, whereinthe second metal organic framework is isostructural with the first metalorganic framework.

Embodiment 20. The process of any one of embodiments 13 to 19, whereinthe first metal organic framework has the structure of UiO-67.

Embodiment 21. An organic compound conversion process comprisingcontacting an organic compound-containing feed with a catalystcomprising the metal organic framework of any one of embodiments 1 to12.

Embodiment 22. An olefin isomerization process comprising contacting anolefin-containing feed with a catalyst comprising the metal organicframework of any one of embodiments 1 to 12.

The invention will now be more particularly described with reference tothe following non-limiting Examples and the accompanying drawings.

The X-ray diffraction data reported in the Examples were collected witha Panalytical X'Pert Pro diffraction system with an Xceleratormultichannel detector, equipped with a germanium solid state detector,using copper K-alpha radiation. The diffraction data were recorded bystep-scanning at 0.02 degrees of two-theta, where theta is the Braggangle, and using an effective counting time of 2 seconds for each step.

EXAMPLE 1 Exchange of 4,4′-biphenylbisphosphonic acid into UiO-67 toproduce EMM-33

2 grams of UiO-67 were charged into a 200 mL round-bottom flask. Theflask was heated to 90° C. 264 mg of biphenylbisphosphonic acid (0.84mmol or 0.22 mol. equivalent) was dissolved in 50 mL ofdimethylsulfoxide and added to the stirring suspension of UiO-67. Thereaction mixture was allowed to stir overnight at 90° C.

The solids were then collected by filtration and washed with 20 mL ofdimethylsulfoxide (DMSO). This wet powder was then suspended in 100 mLof DMSO and stirred overnight at 90° C. to remove any unreacted startingmaterial.

The solids were then filtered and washed with acetonitrile (20 mL), thenre-suspended in 100 mL of acetonitrile and allowed to stir at roomtemperature overnight. The solids were filtered and allowed to dry onthe filter. The powder was then heated at 180° C. under vacuum until apressure of 0.5 mTorr was achieved.

The process was repeated at higher levels of biphenylbisphosphonic acidexchange and the resultant samples were analyzed by powder X-raydiffraction (PXRD), N₂ adsorption, infrared spectroscopy, and nuclearmagnetic resonance spectroscopy. The results are shown in FIGS. 1 to 4respectively and unequivocably demonstrate that the heterolinker wassuccessfully incorporated into the parent UiO-67 framework, although itwill be seen from FIG. 1 that there was some loss of crystallinity athigher levels of phosphonate exchange.

EXAMPLE 2 Catalytic isomerization of 2-methyl-2-pentene by EMM-33

A series of tests of the catalytic activity of the UiO-67 parentmaterial and the EMM-33 produced in Example 1 (at 0.22 mole equivalentexchange) for the isomerization of 2-methyl-2-pentene (2MP=2) wereconducted at temperatures of 250° C. and 350° C. The results are shownin Tables 2 and 3 respectively, where all product composition values arein wt.% and the following abbreviations are used:

-   -   3+4MP=1 designates the total amount of 3-methyl-1-pentene and        4-methyl-1-pentene;    -   4MP=2 designates the total amount of cis- and        trans-4-methyl-2-pentene;    -   2MP=1 designates 2-methyl-1-pentene;    -   3MP=2 designates the total amount of cis- and        trans-3-methyl-2-pentene;    -   23DMB=1 designates 2,3-dimethyl-1-butene;    -   23DMB=2 designates 2,3-dimethyl-2-butene;    -   2EB=1 designates 2-ethyl-1-butene; and    -   t-2H=designates trans 2-hexene, no cis isomer having been        detected.

From Tables 2 and 3, it will be seen that UiO-67 showed essentially nocatalytic activity for the isomerization of 2-methyl-2-pentene, whilethe phosphonate-exchanged EMM-33 material demonstrated moderateisomerization activity as evidenced by the production of2-methyl-1-pentene.

TABLE 2 Isomerization of 2-methyl-2-pentene by UiO-67 Time/ hr Temp.C₁-C₅ 3 + 4MP = 1 4MP = 2 2MP = 1 2MP = 2 3MP = 2 23DMB = 1 23DMB = 22EB = 1 t-2H = 0.08 250 0 0 0 1.384 98.344 0.013 0 0 0 0 1 250 0.016 0 01.261 98.281 0.013 0 0 0 0 2 350 0.016 0 0.008 1.856 98.707 0.058 0 0 00 3 350 0.008 0 0 1.208 98.35 0.012 0 0 0 0

TABLE 3 Isomerization of 2-methyl-2-pentene by EMM-33 Time/ hr Temp.C₁-C₅ 3 + 4MP = 1 4MP = 2 2MP = 1 2MP = 2 3MP = 2 23DMB = 1 23DMB = 22EB = 1 t-2H = 0.08 250 0.006 0.005 0.176 26.93 72.435 0.048 0.08 0.0140 0 1 250 0.038 O 0.032 21.181 78.165 0.062 0 0.006 0 0 2 350 0.0290.045 0.352 31.788 66.962 0.175 0.022 0.057 0.014 0.007 3 350 0.022 00.040 21.403 77.885 0.055 0 0.005 0 0

TABLE 4 Comparison of the isomerization of 2-methylpentene with UiO-67(top), EMM-33 (middle), and EMM-35 (Bottom) Time/Hr Temp/° C. Wt % C1-C5Wt % 4MP = 1 WT % 3MP = 1 WT % 23DMB = 1 c-4MP = 2 t-4MP = 2 UiO-67 0.080 0 0 0 0 0 0 1 0.016 0 0 0 0 0 0 2 0.016 0 0 0 0 0 0.008 3 0.008 0 0 00 0 0 EMM-33 0.08 250 0.021 0.194 0.039 0.13 0.44 2.609 1 250 0.0160.045 0.011 0.047 0.117 0.706 2 350 0.032 0.582 0.14 0.312 0.977 4.128 3250 0.014 0.036 0 0.045 0.122 0.717 EMM-35 0.08 250 0.178 1.35 0.1671.119 2.098 8.864 2 350 0.342 2.566 0.935 2.655 3.093 10.415 3 250 0.050.383 0.083 0.442 0.757 3.588 Time/Hr 2MP = 1 1-H = 2EB = 1 c-&t-3H =t-2H = 2MP = 2 c-3mp = 2 c-2H = t-3MP = 2 23DMP = 2 UiO-67 0.08 1.384 00 0 0 98.344 0 0 0.013 0 1 1.261 0 0 0 0 98.281 0 0 0.013 0 2 1.856 0 00 0 98.707 0.044 0 0.014 0 3 1.208 0 0 0 0 98.35 0 0 0.012 0 EMM-33 0.0822.672 0 0.031 0 0.007 68.824 0.168 0 0.234 0.318 1 27.426 0 0.01 0 070.894 0.072 0 0.069 0.117 2 29.432 0 0.12 0.022 0.043 61.84 0.485 0.0280.742 0.649 3 27.504 0 0.01 0 0 70.747 0.058 0 0.075 0.116 EMM-35 0.0822.346 0 0.21 0.03 0.062 57.894 1.058 0.041 1.719 2.668 2 19.117 0 1.230.297 0.503 40.541 4.803 0.259 7.92 4.868 3 25.11 0 0.077 0.012 0.0266.246 0.386 0.013 0.582 1.146

1. A metal organic framework having the structure of UiO-67 andcomprising bisphosphonate linking ligands.
 2. The metal organicframework of claim 1 and comprising biphenylbisphosphonate linkingligands.
 3. The metal organic framework of claim 2 and comprising4,4′-biphenylbisphosphonate linking ligands.
 4. The metal organicframework of claim 2, wherein at least one of the phenyl groups of thebiphenylbisphosphonate linking ligands is substituted with one or moreelectron withdrawing groups.
 5. The metal organic framework of claim 1and further comprising dicarboxylate linking ligands.
 6. The metalorganic framework of claim 2 and further comprisingbiphenyldicarboxylate linking ligands.
 7. The metal organic framework ofclaim 1, wherein the metal organic framework comprises at least onetetravalent transition metal.
 8. The metal organic framework of claim 7,wherein the at least one tetravalent transition metal is selected fromthe group consisting of hafnium, titanium and zirconium.
 9. A metalorganic framework comprising octahedral nodes at least 6 zirconium atomsand at least 6 oxygen atoms interconnected by biphenyldicarboxylateligands and at least one bisphosphonate linking ligand.
 10. The metalorganic framework of claim 9, wherein the bisphosphonate linking ligandis a biphenylbisphosphonate linking ligand.
 11. The metal organicframework of claim 9, wherein the bisphopsphonate ligand is a4,4′-biphenylbisphosphonate linking ligand.
 12. The metal organicframework of claim 10, wherein at least one of the phenyl groups of thebiphenylbisphosphonate linking ligand is substituted with one or moreelectron withdrawing groups.
 13. The metal organic framework of claim 9,wherein the metal organic framework comprises at least one tetravalenttransition metal.
 14. The metal organic framework of claim 13, whereinthe at least one tetravalent transition metal is selected from the groupconsisting of hafnium, titanium and zirconium.
 15. A process forexchanging an organic linking ligand in a metal organic framework, theprocess comprising: (a) providing a first metal organic frameworkcomprising a three-dimensional microporous crystal framework structurecomprising metal-containing secondary building units connected by firstorganic linking ligands having a first bonding functionality with thesecondary building units, (b) providing a liquid medium containing anorganic compound capable of reacting with the secondary building unitsto produce second organic linking ligands having a second bondingfunctionality with the secondary building units different from the firstbonding functionality; and (c) contacting the first metal organicframework with the liquid medium under conditions effective for theorganic compound to react with the secondary building units in the firstmetal organic framework and exchange at least some of the first organiclinking ligands with second organic linking ligands and produce a secondmetal organic framework.
 16. The process of claim 15, wherein the firstorganic linking ligand is bonded to each secondary building unit througha monoprotic acid group.
 17. The process of claim 16, wherein the firstorganic linking ligand comprises a carboxylic acid.
 18. The process ofclaim 17, wherein the first organic linking ligand comprises an aromaticdicarboxylic acid.
 19. The process of claim 14, wherein the firstorganic linking ligand comprises a biphenyldicarboxylic acid.
 20. Theprocess of claim 19, wherein the second organic linking ligand is bondedto each secondary building unit through a polyprotic acid group.
 21. Theprocess of claim 15, wherein the second organic linking ligand is bondedto each secondary building unit through a diprotic acid group.
 22. Theprocess of claim 15, wherein the second organic linking ligand comprisesa phosphonic acid.
 23. The process of claim 22, wherein the secondorganic linking ligand comprises an aromatic bisphosphonic acid.
 24. Theprocess of claim 23, wherein the second organic linking ligand comprisesa biphenylbisphosphonic acid.
 25. The process of claim 15, wherein thesecondary building units comprise at least one tetravalent transitionmetal.
 26. The process of claim 25, wherein the secondary building unitscomprise at least one metal selected from the group consisting ofhafnium, titanium and zirconium.
 27. The process of claim 15, whereinthe second metal organic framework is isostructural with the first metalorganic framework.
 28. The process of claim 15, wherein the first metalorganic framework has the structure of UiO-67.
 29. An organic compoundconversion process comprising contacting an organic compound-containingfeed with a catalyst comprising the metal organic framework of claim 1.30. An olefin isomerization process comprising contacting anolefin-containing feed with a catalyst comprising the metal organicframework of claim 1.